The invention relates to the controlled activation of the reuterin-production machinery of Lactobacillus reuteri by adding glycerol and other substances during the manufacture of cell-cultures and keeping the produced reuterin in the bacterial cell during preservation and storage. In particular this invention relates to the manufacture of large amounts of L. reuteri that are loaded with reuterin, and the use of such loaded bacteria for applications such as prevention and treatment of diseases, for food applications and the like.